Chaser holder



June 11, 1935.

H. MAURER CHASER HOLDER Filed March 28, 1934 INVENTOR. flaw/y A. Mall/er 9 ATTORNEY Patented June 11, 1935 I t Y CHASER noLnEnj Harry A. Maurer, Novelty; (fine, assi gn or to The 7 t Oster Manufacturing Gompany 3 "Application-March 23, 1934, Serial No. 717,772

U i a d j4fol'aims. (c1, lo -1'20 Y "The Subject of this invention is a holder wherein the cutter or chaser of a thread cutting mechanism is carried. Holders of the sortwhereon this is an improvement, are well known andare ordinarily disposed in a die holding ringin quadrantal arrangement with the cutters all facing inward. An illustration of the use of suchholders may be seen in Figs. 1 and'2 of Hyde Patent No'. 1,921,754, wherein;'holders similar'in func- "tion to those of the present invention, but not fembodying the present improvement, are designated by the referencev character 5. The purposesof this present invention are tosimplify the holder,- to grip the chaser with greater firmness and permanency of alignment than hitheri to, to permit ready attachment and removal of chasers, to minimize wear on the Chasers, and in Q B ofholder. t

general to give to the art'a simplen'stronger, lighter assembly, more easily manufactured and more readily handled than hitherto. A further advantage is the reduction in the amount of expensive alloy steel needed for thechaser, by rea- "son of the reduction in size-of that portion of i the chaser bodywhich is engaged by the holder. To the accomplishment of the foregoing and related ends,,said invention then, consists of the means hereinafter fully describedand particu- .=larly pointed out in' the claims. The annexed "drawing and the following description set forth (in detail certain structure embodyingthe inventiomsuch disclosed means constituting; however,

principle of the inventionsmay' be used.

In the accompanying drawing Fig. l is a perspective view of a front and one side of a holder;

Fig. 2 is a similar view of a chaser; Fig. 3 is a,

similar view of a fastening screw; Fig. 4fis a median longitudinal section through the assembly, limited to the end of the holder, and showing the fastening screw in elevation, this figure being on a larger scale; and Fig. 5 is a front view corresponding to Fig. 4.

V The holder proper comprises a block or barof substantially rectangular shape, as'generally in- V venience of reference the parts of the holder are designated as shown in the drawing, namely,

Throughout the specification and claims the terms front and rear are used with refer ence to the direction of stock feed and the terms face and back are used with reference to the rear edge J.

dicated by the reference character l0. For condirection of rotation between chaser and stock.

Any suitable cam-engaging means will be pro- "vided' for the opening and closing movement -withina die ring such asthe groove II. The

holder is recessed to about half its thickness at one end, as at II, to seat the .shank I3 of the chaser 14. The recess I2 is formed of four surfaces, which for definiteness of designation are indicated onthe accompanying drawing as the back F, the bottom G, the front edge H and the In the preferred embodiment of the invention as illustratedin the drawing these surfaces are mutually perpendicular planes and are parallel to certain planes on the holder block Back F parallel to back E and face D of holder. Bottom G parallel to end A of holder;

.Frontedge' H of recess parallel to front edge Rear edge J of recess parallel to rear edge C "of holder. 1" For convenience of machining the corners of the recess l2 are rounded with some clearancebeyond the edges and bottomof the recess. Itf will'be observed that'all surfaces are readily accessible for machining. hole I6 extends transversely through the holder The size and shape of the shank l3 are such as V :to'fit the recess [2 closely except at the corners. :butone of various structural forms in which the l5, with the face K of the shank flush with the front face of the holder [8. Thus'the chaser bears firmly against the holder recess and over substantially the entire availablearea on the front invention. 7

A smooth hole through the chaser matches the threaded hole H5 in the holder when the chaser is in position. The hole 25 is outwardly enlarged, as at 26, to sink the head of a A threaded screw 3| adapted to take into the threads of 16, 7

thereby fastening the chaser in the holder. When assembled, the head 30 will not stand above the face K of the chaser shank. Theend A of the holder is also chamfered as at 32 in the plane of the usual chamfer 33 at the entering end of the cutter teeth.

The displacing tendency due to the circumferential travel in thread cutting tends to turn the chaser counterclockwise, as seen in Fig. 4, about the edge I2 as a pivot. The lever arm of the turning force is the height of the teeth 20. The screw 3|, which resists this tendency, works on a much longer lever arm, thus holding the chaser firmly and so eliminating the need for a slot in which to seat the chaser.

To assemble the chaser and holder the shank l 3 is put'into the recess I2 and fastened by the screw 3!. Even an unskilled operator cannot accidentally or carelessly put the chaser l4 into the holder with the wrong surface exposed because 7 the head 30 of the'scre'w 3| would then stand above the front plane of *the holden-strike-the equal'in thickness to the depth of said recess,

die ring and soprevent the holder from being moved to work-receiving position.

It will be seen from the foregoing that I have invented a chaser and holder comprising a mini- .mum number of parts the parts being individually simple andreasy to machine, there isno possibility of assembling them incorrectly, there :are noadjustments to be made, and-noelements to get outof order. I

Other modes ofapplying the'principle of my inventionmay be employed instead of the one explained, change being made as regards the'structure. herein disclosed'provided the means stated by any of-thefol-lowing claims or the equivalent of such stated. means be employed.

I therefore particularly point out and distinctly claim as my invention:

l. A chaser and holder comprisingxa holder body, recess'edges therein parallel to the'outer edges thereof and ,extendingwalongsaid holder a :relatively short'distance from one end-thereof,

fitting the corresponding recesssurfaces and'xequal in thickness to the depth of said recess, said blade comprising a chanifer at the work; entrance and cutting teeth adapted to project "beyond the endof said holder whenthe shank is seated, and a chamfer on saidholder end in, prolongation of the blade chamfer; andholdingmeans connecting saidholder and chaser and disposed entirely within the holder body and the chasr' shank.

2. A chaser and holder comprising; a holder body, recess edges therein parallel to the outer edges thereof and extending inward a distance from one end thereof short relative to the size of the chaser, a recess bottom transverse to the recess edges, each of the foregoing recess surfaces intersecting the face of said body, and a recess back parallel to and spaced from the back of said"holder,"said recess edges andback intersecting an end of said holder and all of said recess surfaces jointly defining an open seating recess; -.'a-.chaser comprising a shank and a blade, edges,

bottom and back on said shank closely fitting said respective recess surfaces, said shank being said-blade comprising cutting teeth adapted to project beyond the end of said holder when the shank is seated; and holding means for said chaser comprising :a headed screw threaded into the .earrier body behind said seating recess anda countersunk recess in said shank adapted to receive said screw head.

3. .The combination'of -a holder-and a chaser;

.to.tiltrthe-.chaser act on a lever armequal only .to tooth depth; and a fastener for the chaser face, said fastener being secured in said shank well ,away fromthe .teeth andalso beingsecured in said holder, whereby the fastener actson a longer :lever arm than thetilting strains which itresists.

=4. Thread cutting means comprising a holder of generally rectangular, prismatic form includinga .f-aceD, a backE, an end A, and edges B and C, 'saidholder having atsaid face and end a recess ccmposedofsa back F, edges "H and J, and bot- "tom -.G,--said recess surfaces being respectively :paralleltoback-Elto edges B and C, and to end:A; a 10113 891 adapted .to be carried 'by said holder, .saidchaser'including a shank-shaped'to seat in :said recess :with'back, edges andfbottom in snug afitaagainst-;corresponding elements of the recess,

and with-the face K .of said shank exposed and :not above the: holderfaceD; and: fastening means engaging .said holder-.andsaid :shank not .above "the level of face K.

1HARRY.A.JMAURER. 

